Free CompTIA Linux+ (XK0-006) Practice Questions

Sample XK0-006 Practice Questions

Browse all 10 free CompTIA Linux+ practice questions below.

1. A Linux administrator needs to configure a new RAID 5 array using four 2TB hard drives for a database server. The system requires fault tolerance and optimal read performance. Which command should the administrator use to create the RAID 5 array?

   • mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde
   • lvcreate --raid5 --stripes 4 -L 6TB -n raid5_lv vg0
   • mkraid --level=5 /dev/md0 /dev/sdb /dev/sdc /dev/sdd /dev/sde
   • mdadm --create /dev/md0 --level=1 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde

2. A system administrator notices that the system clock is consistently drifting and causing authentication issues with Kerberos. The server needs accurate time synchronization with multiple time sources for redundancy. Which command should be used to configure NTP time synchronization on a systemd-based Linux distribution?

   • timedatectl set-ntp true
   • chronyd --enable
   • ntpdate -s pool.ntp.org
   • hwclock --systohc

3. A Linux administrator needs to troubleshoot high I/O wait times on a database server. The system is experiencing slow query performance. Which commands should be used to identify the disk I/O bottleneck? (Select TWO)

   • netstat -i
   • iotop -o
   • iostat -xz 1
   • free -h
   • lsof /var

4. A company needs to implement a centralized logging solution for compliance requirements. All Linux servers must forward system logs to a central log server. The solution must use encrypted transport and support structured logging. Which configuration should be implemented?

   • Use syslog-ng with UDP forwarding to the log server on port 514
   • Configure rsyslog with TLS encryption using @@logserver:514 and enable structured logging with templates
   • Set up logrotate to copy logs to NFS share mounted on the central server
   • Configure journald with ForwardToSyslog=yes and use netcat for log forwarding

5. An administrator is configuring a Linux server to boot from a specific kernel version due to hardware compatibility issues. The default GRUB timeout is too short for selection. Which file should be edited to set the kernel and increase the boot menu timeout to 10 seconds?

   • /etc/default/grub - Set GRUB_DEFAULT and GRUB_TIMEOUT=10, then run update-grub or grub2-mkconfig
   • /etc/grub.conf - Modify the timeout parameter and default kernel line
   • /boot/grub/grub.cfg - Directly edit the timeout and default kernel entry
   • /boot/grub2/grubenv - Use grub2-editenv to set timeout and default kernel

6. A DevOps team needs to configure SELinux to allow a custom application to bind to port 8443 for HTTPS traffic. The application is being blocked by SELinux. What is the correct approach to resolve this?

   • semanage port -a -t http_port_t -p tcp 8443
   • Edit /etc/selinux/config and set SELINUX=permissive
   • setenforce 0 to disable SELinux
   • chcon -t http_port_t /path/to/application

7. A Linux administrator needs to monitor real-time CPU usage per core and identify which processes are consuming the most CPU resources on a 16-core server. Which command provides this information most effectively?

   • ps aux | grep CPU
   • vmstat 1
   • sar -u 1
   • htop

8. A system administrator needs to configure a Linux server to automatically mount an NFS share at boot time with specific options: read-write access, version 4, and automatic retry on failure. Which /etc/fstab entry is correct?

   • nfsserver:/share /mnt/data auto rw,noauto 0 0
   • nfsserver:/share /mnt/data nfs defaults,vers=4 0 0
   • //nfsserver/share /mnt/data cifs rw,vers=4.0 0 0
   • nfsserver:/share /mnt/data nfs4 rw,_netdev,x-systemd.automount 0 0

9. An organization's security policy requires that all user passwords must be at least 12 characters long, contain mixed case, numbers, and special characters. Failed login attempts must be limited to 3 before account lockout. Which configuration files need to be modified? (Select TWO)

   • /etc/pam.d/common-auth or /etc/pam.d/system-auth - Configure pam_faillock for account lockout
   • /etc/security/pwquality.conf - Configure password complexity requirements
   • /etc/shadow - Manually edit password hashes and lock accounts
   • /etc/ssh/sshd_config - Set PasswordAuthentication and MaxAuthTries
   • /etc/login.defs - Set PASS_MAX_DAYS and PASS_MIN_LEN

10. A developer reports that a systemd service fails to start after a server reboot, but works when started manually with 'systemctl start appservice'. The service requires network connectivity to a database server. What is the most likely cause and solution?

    • SELinux blocking - Run 'setenforce 0' to disable SELinux
    • Permission issue - Change service file ownership to root and set chmod 755
    • Missing network dependency - Add 'After=network-online.target' and 'Wants=network-online.target' to the service unit file
    • Service is disabled - Run 'systemctl enable appservice' to enable automatic startup